This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Proper transmission of genetic material requires the correct assembly and function of a molecular machine called the mitotic spindle. Errors in spindle assembly result in missegregation of the chromosomes and can lead to disability and cancer. Some cancer cells over express components of the kinetochore. The kinetochore, critical for correct spindle assembly, is a site of regulation and checkpoint signaling. Because errors in spindle assembly result in disease, it is important to understand the precise function of each spindle component. Already, cancer therapies targeting mitotic cells have been used with great success. Continued research in this area will lead to new, more specific drugs, whose primary target is diseased cells.